It is a major problem in cold climates to prevent condensation within the insulated ceiling structure of moisture condensed from the hot, moist inside air within the building. This is particularly true in vaulted interior ceiling constructions where frequently, there is insufficient vented air circulation provided between the insulated portion of the roof structure and the cold outside exposed roofing layer.
The present invention provides a double layer construction with cold vented air circulation passage means between the insulation and the outer roofing layer.